1. Field of the Invention
The present invention relates to an information recording and/or reproducing apparatus which can be applied to magneto-electrical characteristic inspection systems for servo track writers, heads, head gimbal assemblies, head stack assemblies, or the like of hard disk drives, and to magneto-electrical characteristic inspection systems for hard disks themselves and which can also be applied to inspection/manufacturing apparatus for optical or magnetooptical recording heads, optical or magnetooptical recording disks, and so on.
2. Related Background Art
The conventional information recording and/or reproducing apparatus of this type is comprised of a disk driving mechanism for rotationally driving a disk as an information recording medium, a head positioning mechanism for positioning a head for recording or reproducing information, relative to the disk, a control circuit for controlling these disk driving mechanism and head positioning mechanism, and so on.
For example, as illustrated in FIG. 1, the disk driving mechanism is composed of a first spindle motor 1, an air bearing 2, a disk 3, a clamper 4, a first encoder 5, and so on, and the head positioning mechanism is composed of a second spindle motor 6, heads 7, gimbal assemblies 8, a loader 9, a second encoder 10, and so on. The control circuit is constructed in such a configuration that a first or second driving circuit 11 or 12 is connected to the first or second spindle motor 1 or 6, respectively, and that a first or second control circuit 13 or 14 is connected to the first or second driving circuit 11 or 12, respectively. A clock circuit 15 is coupled to the first control circuit 13, and the second control circuit 14 and clock circuit 15 are connected to a computer 16.
The computer 16 outputs a target speed of the disk 3 via the clock circuit 15 to the first control circuit 13 and the first encoder 5 outputs an actual speed of the disk 3 to the first control circuit 13. The first control circuit 13 compares the actual speed with the target speed and then outputs a difference between these speeds to the first driving circuit 11. Then the first driving circuit 11 drives the first spindle motor 1 so as to match the actual speed with the target speed. The disk 3 will be rotated at the target speed after repetition of these processes.
The computer 16 outputs a target position of the head 7 to the second control circuit 14 and the second encoder 10 outputs an actual position of the head 7 to the second control circuit 14. The second control circuit 14 compares the present position with the target position and outputs a difference between these positions to the second driving circuit 12. Then the second driving circuit 12 drives the second spindle motor 6 so as to match the actual position with the target position. The head 7 will be set at the target position after repetition of these processes.
In the above conventional example, however, even if the head 7 is set, for example, with the accuracy of xc2x110 nm, where a nonsynchronous radial runout (NRRO) of the first spindle motor 1 is 30 nm, the maximum deviation will be 50 nm between relative positions of the head 7 to the disk 3. For this reason, supposing a permissible error of track pitch of the disk 3 is 2%, the number of tracks is limited to 10160 per inch and it becomes hard to record or reproduce the information with high accuracy.
In view of the above, an object of the present invention is to provide an information recording and/or reproducing apparatus that can record and/or reproduce information with higher accuracy.
Other objects of the present invention will become apparent in the description of embodiments detailed hereinafter.
For accomplishing the above object, an information recording and/or reproducing apparatus comprises a first driving motor for supporting and rotationally driving a disk of an information recording medium, a head for recording or reproducing information in or from the disk, and a second driving motor for supporting and rotationally driving the head, the apparatus further comprising a sensor for gaining a nonsynchronous deflection component of a rotating part of said first driving-motor, and the second motor is controlled based on an output of the sensor to make the head track the nonsynchronous deflection component.